1. Field of the Invention
The present invention relates to a cooling device for a semiconductor element module and a magnetic part, comprising: a water-cooled type heat sink having a cooling water passage; a semiconductor element module including a plurality of chips arranged side by side in a circulation direction in the cooling water passage, the semiconductor element module being mounted on the heat sink; and a magnetic part including a core and a winding portion mounted on the core, the magnetic part being mounted on the heat sink or another heat sink.
2. Description of the Related Art
A cooling device as follows has already been known from Japanese Patent Application Laid-open No. 2004-349324. The cooling device includes cooling fins disposed in a cooling water passage of a heat sink in order to improve the cooling performance of the heat sink on which semiconductor element modules are mounted. The cooling fins are extended along the circulation direction of the cooling water passage, and are formed to be integrally connected to each other along the entire cooling water passage.
In the meantime, the following is known. When cooling water flows through a cooling water passage, there is a thermal entrance region associated with a change in the flow velocity distribution near the inlet of the cooling water passage. In the thermal entrance region, the thermal conductivity decreases in a downstream direction. After the cooling water passes through the thermal entrance region, the thermal conductivity approaches to a constant thermal conductivity in a hydrodynamically developed region where the flow velocity becomes constant. Thus, the cooling device formed by integrally connecting the cooling fins extending along the circulation direction of the cooling water passage across the entire length of the cooling water passage as disclosed in the Japanese Patent Application Laid-open No. 2004-349324 has a thermal entrance region only at the inlet of the cooling water passage, thus it is difficult to obtain high heat transfer efficiency for the entire cooling water passage.